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EP0166019A1 - Method for desulfurizing pig iron - Google Patents

Method for desulfurizing pig iron Download PDF

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Publication number
EP0166019A1
EP0166019A1 EP84107487A EP84107487A EP0166019A1 EP 0166019 A1 EP0166019 A1 EP 0166019A1 EP 84107487 A EP84107487 A EP 84107487A EP 84107487 A EP84107487 A EP 84107487A EP 0166019 A1 EP0166019 A1 EP 0166019A1
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EP
European Patent Office
Prior art keywords
blown
pig iron
lime
gas
weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP84107487A
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German (de)
French (fr)
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EP0166019B1 (en
Inventor
Rudolf Dr.-Ing. Hammer
Walter Dipl.-Ing. Meichsner
Karl-Heinz Dr.-Ing. Peters
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Thyssen Stahl AG
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Thyssen Stahl AG
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Priority to DE8484107487T priority Critical patent/DE3474568D1/en
Priority to AT84107487T priority patent/ATE37902T1/en
Priority to EP84107487A priority patent/EP0166019B1/en
Priority to US06/743,854 priority patent/US4586955A/en
Priority to CA000485473A priority patent/CA1239022A/en
Priority to AU44244/85A priority patent/AU570805B2/en
Priority to CN85104955.9A priority patent/CN1003308B/en
Publication of EP0166019A1 publication Critical patent/EP0166019A1/en
Application granted granted Critical
Publication of EP0166019B1 publication Critical patent/EP0166019B1/en
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising

Definitions

  • the present invention relates to a process for the desulfurization of pig iron in a ladle which receives the pig iron, in particular in a torpedo pan, with a diving lance in which aluminum and then lime are blown into the pig iron with the aid of a carrier gas.
  • lime-based desulphurization agents have also been proposed. However, they have the disadvantage that large amounts are required to achieve the desired desulfurization effect. In practice, this leads to considerable Difficulties due to the large amounts of slag produced.
  • the considerable volume of the large amounts of slag in the pan leads to a corresponding reduction in the transport capacity of the pan.
  • the slags tend to stick to the pan walls, which further limits the transport capacity.
  • the slags also contain large amounts of iron droplets, which lead to significant iron losses.
  • a further development in the use of lime as a desulfurization agent is to add aluminum to the desulfurization agent (DE-AS 25 31 047) or first to blow aluminum and then lime into the pig iron with the aid of large amounts of conveying gas.
  • the large amounts of a non-oxidizing gas, such as nitrogen, to promote the lime also serve to disperse the lime particles in the pig iron melt and to generate a bath circulation.
  • a non-oxidizing gas such as nitrogen
  • the object of the present invention is to reduce both the amount of feed gas required and the consumption of the calcareous desulfurization agent.
  • the object is achieved according to the characterizing part of claim 1 by blowing in a solid in the pig iron melt with a quantity of 2 - 20 N1 carrier gas / kg desulfurizing agent together with the lime.
  • the gas-releasing solid preferably consists of an alkaline earth carbonate and / or an alkaline earth hydrate, limestone or dolomite being blown in as alkaline earth carbonate with particular advantage and hydrated lime hydrate as alkaline earth metal hydrate.
  • the aluminum is preferably blown into the melt in a fine-grained form with the aid of a carrier gas.
  • a carrier gas e.g., ethylene glycol
  • 0.2-0.7 kg aluminum per ton of pig iron is mixed with an inert gas such as e.g. Blow propane, nitrogen or argon into the pig iron in 1 - 4 minutes.
  • the desulfurizing agent mixture preferably consists of 40-70% lime and 30-60 wt.% Gas-releasing solid. Small additions of carbon or carbon-containing substances such as carbon black, anthracite, graphite, petroleum coke, in the range of 1-10 wt.% Of the desulfurizing agent mixture are preferred added. This improves the flow properties of the blown-in mixture, and reducing conditions are created in the melt as a prerequisite for good desulfurization.
  • the blown-in mixture can contain 1-10% by weight of fluorspar.
  • Fluorspar (CaFz) lowers the enamel point of the aluminates formed, which therefore do not solidify as easily when the temperature of the melt is lowered.
  • the iron content absorbed by the melt is reduced.
  • the amount of aluminum and the amount of desulfurizing agent mixture depend on the desired degree of desulfurization.
  • a flow improver and / or a protective substance can be blown in together with the aluminum.
  • the lower amounts of desulfurizing agent lead to a reduction in the desulfurization slag formed and, associated therewith, to a reduction in iron losses.
  • the lower formation of slag causes less formation of slag in the torpedo pan and, seen over a longer period of time, leads to the capacity of the torpedo pan being changed only slightly. This also means that the bath geometry in the torpedo pan hardly changes, so that the favorable conditions remain constant over a longer period of time.
  • the amount of feed gas amounted to 75 Nl / kg of solid, both for blowing in the aluminum powder and for blowing in the lime.
  • the immersion lance which was provided with a thick refractory coating, had two nozzle-shaped outlet openings and therefore had to be inserted vertically through the mouth opening of the torpedo pan.
  • the desulfurization agent consisting of 60% by weight of lime, 40% by weight of limestone and 0.05% by weight of flow improver in the form of propyl alcohol blown into the melt using compressed air as the carrier gas.
  • the amount of feed gas was 5 Nl / kg solid.
  • a simple tube with a thin refractory coating was used as a lance, which was dipped diagonally into the pig iron. Despite the reduction in the blowing time from 25 to 12 minutes (including Al blowing) and a higher filling level of the torpedo pan, there was no significant cast iron ejection.
  • the desulfurization agent consisting of 55% by weight of lime, 35% by weight of lime hydrate, 5% by weight of CaF z , 5% by weight of anthracite and 0.03% by weight of flow improver in the form of Monoglyceride is blown into the melt using compressed air as the carrier gas.
  • the amount of feed gas was 4 Nl / kg.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Treatment Of Steel In Its Molten State (AREA)

Abstract

The invention relates to a process for desulphurizing hot metal in a ladle, in particular in a torpedo ladle, wherein first aluminum and then, by means of a carrier gas, lime (CaO) are blown into the hot metal. The characterizing feature of the invention is that at a rate of 2-20 liters (S.T.P.) of carrier gas/kg of desulphurizing agent, a solid which evolves a gas in the hot metal is blown in together with the lime.

Description

Die vorliegende Erfindung betrifft ein Verfahren zur Entschwefelung von Roheisen in einer das Roheisen aufnehmenden Pfanne, insbesondere in einer Torpedopfanne, mit einer Tauchlanze bei dem zunächst Aluminium und anschließend Kalk mit Hilfe eines Trägergases in das Roheisen eingeblasen werden.The present invention relates to a process for the desulfurization of pig iron in a ladle which receives the pig iron, in particular in a torpedo pan, with a diving lance in which aluminum and then lime are blown into the pig iron with the aid of a carrier gas.

Das Einblasen von feinkörnigen Entschwefelungsmitteln in Roheisen hat in den letzten Jahren zunehmend an Bedeutung gewonnen. Bei diesen Verfahren werden hauptsächlich Mittel auf der Basis von Calciumcarbid und Magnesium verwendet. Diese Entschwefelungsmittel besitzen zwar eine hohe Wirksamkeit, sind jedoch relativ teuer.The blowing of fine-grained desulfurization agents into pig iron has become increasingly important in recent years. These processes mainly use agents based on calcium carbide and magnesium. Although these desulfurizing agents are highly effective, they are relatively expensive.

Da Kalk ein relativ preiswertes Mittel ist, sind daher auch Entschwefelungsmittel auf Kalkbasis vorgeschlagen worden. Sie besitzen jedoch den Nachteil, daß große Mengen für die Erzielung des gewünschten Entschwefelungseffektes erforderlich sind. Das führt in der Praxis zu erheblichen Schwierigkeiten wegen der entstehenden großen Schlackenmengen. Das erhebliche Volumen der großen Schlackenmengen in der Pfanne führt zu einer entsprechenden Verringerung der Transportkapazität der Pfanne. Außerdem neigen die Schlacken dazu, sich an den Pfannenwänden festzusetzen, wodurch die Transportkapazität noch weiter eingeschränkt wird. Die Schlacken enthalten ferner große Mengen an Eisentröpfchen, die zu erheblichen Eisenverlusten führen.Since lime is a relatively inexpensive medium, lime-based desulphurization agents have also been proposed. However, they have the disadvantage that large amounts are required to achieve the desired desulfurization effect. In practice, this leads to considerable Difficulties due to the large amounts of slag produced. The considerable volume of the large amounts of slag in the pan leads to a corresponding reduction in the transport capacity of the pan. In addition, the slags tend to stick to the pan walls, which further limits the transport capacity. The slags also contain large amounts of iron droplets, which lead to significant iron losses.

Eine Weiterentwicklung bei der Verwendung von Kalk als Entschwefelungsmittel besteht darin, Aluminium dem Entschwefelungsmittel beizumischen (DE-AS 25 31 047) oder zunächst Aluminium und anschließend Kalk mit Hilfe großer Fördergasmengen in das Roheisen einzublasen. Die großen Mengen an einem nichtoxydierenden Gas, wie beispielsweise Stickstoff, zur Förderung des Kalkes dienen auch der Dispergierung der Kalkteilchen in der Roheisenschmelze und zur Erzeugung eines Badumlaufes. Es ergeben sich dabei jedocheerhebliche Nachteile, da durch unvollständige Dispergierung der Kalk nicht seine volle Wirkung entfalten kann und ein erhebliches Verspritzen des Roheisens infolge der großen Fördergasmengen eintritt (SDS-Verfahren der Nippon Steel Corporation). Auch ist ein starker voreilender Verschleiß der feuerfesten Auskleidung der Pfanne im Mündungsbereich zu beachten.A further development in the use of lime as a desulfurization agent is to add aluminum to the desulfurization agent (DE-AS 25 31 047) or first to blow aluminum and then lime into the pig iron with the aid of large amounts of conveying gas. The large amounts of a non-oxidizing gas, such as nitrogen, to promote the lime also serve to disperse the lime particles in the pig iron melt and to generate a bath circulation. However, there are considerable disadvantages, since incomplete dispersion of the lime cannot develop its full effect and there is considerable splashing of the pig iron as a result of the large amounts of conveying gas (SDS process from Nippon Steel Corporation). There must also be a lot of premature wear on the refractory lining of the pan in the mouth area.

Bei bekannten Entschwefelungsverfahren, die mit Kalk als Entschwefelungsmittel arbeiten, verbindet sich der aus der Reaktion Ca0 + S = CaS + 0 entstehende Sauerstoff mit dem Silicium des Roheisens zu Si02. Diese Kieselsäure bildet mit dem eingeblasenen Kalk Dicalciumsilikat, welches das Kalkkorn mit einer festen Schicht umgibt. Hierdurch wird die Entschwefelungswirkung des Kalkkornes nachteilig beeinflußt.In known desulfurization processes that use lime as the desulfurization agent, the oxygen resulting from the reaction Ca0 + S = CaS + 0 combines with the silicon of the pig iron to Si0 2 . This silica forms dicalcium with the blown-in lime silicate, which surrounds the grain of lime with a solid layer. As a result, the desulfurization effect of the lime grain is adversely affected.

Bei den bekannten Entschwefelungsverfahren mit Kalk, bei denen zusätzlich Aluminium in die Schmelze eingeblasen wird, wird der aus der Entschwefelungsreaktion Ca0 + S entstehende Sauerstoff von den in die Schmelze eingeblasenen Aluminiumteilchen zu Al2O3 abgebunden. Das gebildete Aluminiumoxyd verbindet sich mit dem eingeblasenen Kalk zu Calciumaluminat CaOAl2O3 . Hierbei handelt es sich im Gegensatz zum festen Dicalciumsilicat um eine flüssige Verbindung mit guter Entschwefelungswirkung.In the known desulphurization processes with lime, in which aluminum is additionally blown into the melt, the oxygen resulting from the desulfurization reaction Ca0 + S is bound to Al 2 O 3 by the aluminum particles blown into the melt. The aluminum oxide formed combines with the blown-in lime to form calcium aluminate CaOAl 2 O 3 . In contrast to solid dicalcium silicate, this is a liquid compound with a good desulfurization effect.

Die vorliegende Erfindung hat sich die Aufgabe gestellt, sowohl die erforderliche Fördergasmenge als auch den Verbrauch des kalkhaltigen Entschwefelungsmittels zu verringern.The object of the present invention is to reduce both the amount of feed gas required and the consumption of the calcareous desulfurization agent.

Die Aufgabe wird nach dem Kennzeichen von Anspruch 1 dadurch gelöst, daß mit einer Menge von 2 - 20 N1 Trägergas/kg Entschwefelungsmittel zusammen mit dem Kalk ein in der Roheisenschmelze gasabspaltender Feststoff eingeblasen wird.The object is achieved according to the characterizing part of claim 1 by blowing in a solid in the pig iron melt with a quantity of 2 - 20 N1 carrier gas / kg desulfurizing agent together with the lime.

Es hat sich überraschenderweise gezeigt, daß die kennzeichnende Verfahrenskombination unter Zuhilfenahme eines gasabspaltenden Feststoffs und der beschriebenen geringen Fördergasmenge zu einer hervorragenden Entschwefelungswirkung und einer gut beherrschbaren betrieblichen Anwendung führt.It has surprisingly been found that the characteristic process combination with the aid of a gas-releasing solid and the small amount of conveying gas described leads to an excellent desulfurization effect and a well-controllable operational application.

Der gasabspaltende Feststoff besteht bevorzugt aus einem Erdalkalicarbonat und/oder einem Erdalkalihydrat, wobei als Erdalkalicarbonat mit besonderem Vorteil Kalkstein oder Dolomit bzw. als Erdalkalihydrat Kalkhydrat eingeblasen wird.The gas-releasing solid preferably consists of an alkaline earth carbonate and / or an alkaline earth hydrate, limestone or dolomite being blown in as alkaline earth carbonate with particular advantage and hydrated lime hydrate as alkaline earth metal hydrate.

Diese Stoffe spalten bei Erhitzung in der Roheisenschmelze spontan CO2 oder Wasserdampf ab und bewirken eine intensive Dispergierung der Kalkteilchen in der Roheisenschmelze sowie eine für den Konzentrationsausgleich unerläßliche, intensive Umwälzströmung des Roheisenbades.When heated in the pig iron melt, these substances spontaneously split off CO 2 or water vapor and cause an intensive dispersion of the lime particles in the pig iron melt as well as an intensive circulation flow of the pig iron bath, which is essential for the concentration compensation.

C02 und Wasserdampf sind jedoch bei Roheisentemperaturen stark oxydierend; nach thermodynamischen Gesichtspunkten muß der Fachmann somit eine vollständige Reaktion mit dem eingebrachten Aluminium nach den Gleichungen

Figure imgb0001
Figure imgb0002
Figure imgb0003
erwarten.However, CO 2 and water vapor are strongly oxidizing at pig iron temperatures; From a thermodynamic point of view, the person skilled in the art must therefore have a complete reaction with the aluminum introduced according to the equations
Figure imgb0001
Figure imgb0002
Figure imgb0003
expect.

Überraschenderweise hat sich jedoch gezeigt, daß der Verbrauch an Entschwefelungsmittel durch das erfindungsgemäße Verfahren erheblich reduziert werden kann und die erwähnten Nachteile nicht eintreten. Durch die geringen Fördergasmengen von 2 - 20, bevorzugt 3 - 8 NL/kg Entschwefelungsmittel ist eine betriebsgerechte Arbeitsweise möglich. Es tritt weder Auswurf aus der Torpedopfanne noch nennenswerte Verbärung der Pfannen auf. Der bei hohen Fördergasmengen typische Verschleiß der feuerfesten Auskleidung wird wirksam unterdrückt. Außerdem kann aufgrund der geringen Fördergasmenge ohne Beeinträchtigung der Entschwefelungsreaktionen nach einem weiteren Merkmal der Erfindung preiswerte komprimierte Luft (Preßluft) anstelle der sonst erforderlichen teureren Trägergase, wie Stickstoff, verwendet werden.Surprisingly, however, it has been shown that the consumption of desulfurizing agent can be considerably reduced by the process according to the invention and the disadvantages mentioned do not occur. Due to the low conveying gas quantities of 2 - 20, preferably 3 - 8 NL / kg desulphurizing agent, an operationally appropriate way of working is possible. There is no ejection from the torpedo pan and no significant parsing of the pans. The wear and tear of the refractory lining, which is typical for high amounts of conveying gas, is effectively suppressed. In addition, according to a further feature of the invention, inexpensive compressed air (compressed air) can be used instead of the more expensive carrier gases, such as nitrogen, which would otherwise be required, without impairing the desulfurization reactions.

Das Aluminium wird bevorzugt in feinkörniger Form mit Hilfe eines Trägergases in die Schmelze eingeblasen. Es ist jedoch auch möglich das Aluminium in Drahtform mit Hilfe einer entsprechenden Vorrichtung in das Roheisen einzuführen.The aluminum is preferably blown into the melt in a fine-grained form with the aid of a carrier gas. However, it is also possible to introduce the aluminum in wire form into the pig iron with the aid of an appropriate device.

Gemäß einer bevorzugten Ausführungsform der Erfindung wird 0,2 - 0,7 kg Aluminium je Tonne Roheisen mit einem Inertgas wie z.B. Propan, Stickstoff oder Argon in 1 - 4 Minuten in das Roheisen eingeblasen. Das Entschwefelungsmittelgemisch besteht bevorzugt aus 40 - 70% Kalk und 30 - 60 Gew.-% gasabspaltendem Feststoff Bevorzugt werden geringe Beimengungen an Kohlenstoff oder kohlenstoffhaltigen Substanzen wie Ruß, Anthrazit, Graphit, Petrolkoks, im Bereich von 1 - 10 Gew.-% dem Entschwefelungsmittelgemisch zugesetzt. Hierdurch wird die Fließeigenschaft des eingeblasenen Gemisches verbessert, und es werden in der Schmelze reduzierende Bedingungen geschaffen als Voraussetzung für eine gute Entschwefelung.According to a preferred embodiment of the invention, 0.2-0.7 kg aluminum per ton of pig iron is mixed with an inert gas such as e.g. Blow propane, nitrogen or argon into the pig iron in 1 - 4 minutes. The desulfurizing agent mixture preferably consists of 40-70% lime and 30-60 wt.% Gas-releasing solid. Small additions of carbon or carbon-containing substances such as carbon black, anthracite, graphite, petroleum coke, in the range of 1-10 wt.% Of the desulfurizing agent mixture are preferred added. This improves the flow properties of the blown-in mixture, and reducing conditions are created in the melt as a prerequisite for good desulfurization.

Ferner kann das eingeblasene Gemisch 1 - 10 Gew.-% Flußspat enthalten. Flußspat (CaFz ) erniedrigt den Schmelzpunkt der gebildeten Aluminate, die daher bei Temperaturerniedrigung der Schmelze nicht so.leicht erstarren. Außerdem wird der von der Schmelze aufgenommene Eisengehalt verringert.Furthermore, the blown-in mixture can contain 1-10% by weight of fluorspar. Fluorspar (CaFz) lowers the enamel point of the aluminates formed, which therefore do not solidify as easily when the temperature of the melt is lowered. In addition, the iron content absorbed by the melt is reduced.

Die Menge an Aluminium und die Menge an Entschwefelungsmittelgemisch richten sich dabei nach dem gewünschten Entschwefelungsgrad.The amount of aluminum and the amount of desulfurizing agent mixture depend on the desired degree of desulfurization.

Aus fördertechnischen Gründen und zur Vermeidung von Aufschmelzungen von Aluminium in der Tauchlanze kann gemeinsam mit dem Aluminium noch ein Fließverbesserer und/oder ein Schutzstoff eingeblasen werden.For reasons of conveying technology and to avoid melting aluminum in the immersion lance, a flow improver and / or a protective substance can be blown in together with the aluminum.

Neben den bereits genannten Vorteilen, die mit der Erfindung erzielt werden, führendie geringeren Entschwefelungsmittelmengen zu einer Verringerung der gebildeten Entschwefelungsschlacke und damit zusammenhängend zu einer Verringerung der Eisenverluste. Die geringere Schlackenbildung bedingt eine geringere Ansatzbildung von Schlacken in der Torpedopfanne und führt über einen längeren Zeitraum gesehen dazu, daß die Kapazität der Torpedopfanne nur geringfügig geändert wird. Dies führt weiter dazu, daß die Badgeometrie in der Torpedopfanne sich kaum ändert, so daß die günstigen Bedingungen über einen längeren Zeitraum konstant bleiben.In addition to the advantages already mentioned, which are achieved with the invention, the lower amounts of desulfurizing agent lead to a reduction in the desulfurization slag formed and, associated therewith, to a reduction in iron losses. The lower formation of slag causes less formation of slag in the torpedo pan and, seen over a longer period of time, leads to the capacity of the torpedo pan being changed only slightly. This also means that the bath geometry in the torpedo pan hardly changes, so that the favorable conditions remain constant over a longer period of time.

Die Erfindung wird nachstehend anhand von Ausführungsbeispielen weiter erläutert.The invention is further explained below using exemplary embodiments.

Beispiel 1example 1

Bei diesem nicht unter die Erfindung fallenden Vergleichsbeispiel wurden zunächst 0,4 kg Aluminiumpulver pro Tonne Roheisen in 185 t Roheisen, die sich in einer Torpedopfanne von 240 t Fassungsvermögen befanden, während einer Zeit von 3,6 min eingeblasen. Anschließend wurde das aus Kalk bestehende Entschwefelungsmittel mit einer Tauchlanze mit Stickstoff als Fördergas eingeblasen. Die Roheisenschmelze hatte einen Ausgangsschwefelgehalt von SA=0,035%. Nach 21,7 min Behandlungsdauer waren 1170 kg Entschwefelungsmittel eingeblasen worden, das entspricht 6,3 kg/t Roheisen. Der Endschwefelgehalt nach der Behandlung betrug SE=0,015%. Die Fördergasmenge belief sich auf 75 Nl/kg Feststoff, sowohl für das Einblasen des Aluminiumpulvers als auch für das Einblasen des Kalkes. Die Förderrate des Kalkes, bedingt durch die erforderliche hohe Gasmenge, betrug 54 kg/min. Hieraus ergibt sich eine Einblaszeit von insgesamt 25 min.In this comparative example not falling within the scope of the invention, 0.4 kg of aluminum powder per ton of pig iron was first used in 185 t of pig iron, which were in a torpedo pan with a capacity of 240 t were blown in over a period of 3.6 min. Then the desulphurising agent consisting of lime was blown in with a diving lance with nitrogen as the conveying gas. The pig iron melt had an initial sulfur content of S A = 0.035%. After 21.7 minutes of treatment, 1170 kg of desulfurizing agent had been blown in, which corresponds to 6.3 kg / t of pig iron. The final sulfur content after the treatment was S E = 0.015%. The amount of feed gas amounted to 75 Nl / kg of solid, both for blowing in the aluminum powder and for blowing in the lime. The lime flow rate, due to the high gas volume required, was 54 kg / min. This results in a total blowing time of 25 minutes.

Trotz der begrenzten Pfannenfüllung trat erhebliches Verspritzen von Roheisen aus der Mündung der Torpedopfanne auf. Die mit einer dicken Feuerfestbeschichtung versehene Tauchlanze hatte zwei düsenförmige Austrittsöffnungen und mußte aus diesem Grunde senkrecht durch die Mündungsöffnung der Torpedopfanne eingeführt werden.Despite the limited pan filling, there was considerable splashing of pig iron from the mouth of the torpedo pan. The immersion lance, which was provided with a thick refractory coating, had two nozzle-shaped outlet openings and therefore had to be inserted vertically through the mouth opening of the torpedo pan.

Beispiel 2Example 2

Bei diesem erfindungsgemäßen Beispiel wurden in der ersten Stufe 0,2 kg Aluminiumpulver pro Tonne Roheisen während einer Zeit von 2,5 min über eine Tauchlanze mit Argon als Trägergas in die Schmelze eingeblasen. Das Roheisen hatte ein Gewicht von 200 t, das Fassungsvermögen der Torpedopfanne betrug wieder 240 t.In this example according to the invention, in the first stage, 0.2 kg of aluminum powder per ton of pig iron was blown into the melt over a immersion lance with argon as the carrier gas over a period of 2.5 min. The pig iron had a weight of 200 t, the capacity of the torpedo pan was again 240 t.

In der zweiten Stufe wurde das Entschwefelungsmittel, bestehend aus 60 Gew.-% Kalk, 40 Gew.-% Kalkstein und 0,05 Gew.-% Fließverbesserer in Form von Propylalkohol mit Hilfe von Preßluft als Trägergas in die Schmelze eingeblasen. Die Roheisenschmelze hatte einen Ausgangsschwefelgehalt von SA=0.038 %, nach 8 min Behandlungsdauer waren 700 kg Entschwefelungsmittel eingeblasen worden. Das entspricht 3,5 kg/t Roheisen. Der Schwefelendgehalt nach der Behandlung betrug SE=0,012%. Die Fördergasmenge betrug 5 Nl/kg Feststoff.In the second stage, the desulfurization agent consisting of 60% by weight of lime, 40% by weight of limestone and 0.05% by weight of flow improver in the form of propyl alcohol blown into the melt using compressed air as the carrier gas. The pig iron melt had an initial sulfur content of S A = 0.038%; after 8 minutes of treatment, 700 kg of desulfurizing agent had been blown in. This corresponds to 3.5 kg / t of pig iron. The final sulfur content after the treatment was S E = 0.012%. The amount of feed gas was 5 Nl / kg solid.

Als Lanze wurde ein einfaches mit einer dünnen Feuerfestbeschichtung versehenes Rohr verwendet, welches schräg in das Roheisen eingetaucht wurde. Trotz der Herabsetzung der Einblaszeit von 25 auf 12 min (einschl. des Al-Einblasens) und eines höheren Füllgrades der Torpedopfanne trat kein nennenswerter Roheisenauswurf auf.A simple tube with a thin refractory coating was used as a lance, which was dipped diagonally into the pig iron. Despite the reduction in the blowing time from 25 to 12 minutes (including Al blowing) and a higher filling level of the torpedo pan, there was no significant cast iron ejection.

Beispiel 3Example 3

Bei diesem erfindungsgemäßen Beispiel wurden in der ersten Stufe 0,4 kg Aluminiumpulver pro Tonne Roheisen während einer Zeit von 4 min über eine Tauchlanze mit Propan als Trägergas in die Schmelze eingeblasen. Das Roheisengewicht betrug 181 t, das Fassungsvermögen der Torpedopfanne belief sich auf 200 t.In this example according to the invention, in the first stage 0.4 kg of aluminum powder per ton of pig iron was blown into the melt over a period of 4 minutes using a submersible lance with propane as the carrier gas. The pig iron weight was 181 t, the capacity of the torpedo pan was 200 t.

In der zweiten Stufe wurde das Entschwefelungsmittel, bestehend aus 55 Gew.-% Kalk, 35 Gew.-% Kalkhydrat, 5 Gew.-% CaFz, 5 Gew.-% Anthrazit und 0,03 Gew.-% Fließverbesserer in Form von Monoglyzerid mit Hilfe von Preßluft als Trägergas in die Schmelze eingeblasen. Die Roheisenschmelze hatte einen Ausgangsschwefelgehalt von SA=0,015%, nach 6,7 min Behandlungsdauer waren 650 kg Entschwefelungsmittel eingeblasen worden. Das entspricht 3,6 kg/t Roheisen. Der Schwefelendgehalt nach der Behandlung betrug SE=0,003%. Die Fördergasmenge betrug 4 Nl/kg. Auch bei diesem Ausführungsbeispiel wurde ein einfaches mit einer dünnen Feuerfestbeschichtung versehenes Rohr verwendet, welches schräg in das Roheisen eingetaucht wurde. Die Einblaszeit betrug nur 10,7 min einschl. des Al-Einblasens. Auch bei diesem erfindungsgemäßen Beispiel trat kein nennenswerter Roheisenauswurf auf.In the second stage, the desulfurization agent, consisting of 55% by weight of lime, 35% by weight of lime hydrate, 5% by weight of CaF z , 5% by weight of anthracite and 0.03% by weight of flow improver in the form of Monoglyceride is blown into the melt using compressed air as the carrier gas. The pig iron melt had an initial sulfur content of S A = 0.015%; after 6.7 minutes of treatment, 650 kg of desulfurizing agent had been blown in. This corresponds to 3.6 kg / t of pig iron. The final sulfur content after the treatment was S E = 0.003%. The amount of feed gas was 4 Nl / kg. Even with this execution For example, a simple tube with a thin refractory coating was used, which was dipped into the pig iron at an angle. The blowing time was only 10.7 min. Including the Al blowing. In this example according to the invention, too, no significant pig iron ejection occurred.

Claims (8)

1. Verfahren zum Entschwefeln von Roheisen in einer Pfanne, insbesondere in einer Torpedopfanne, bei dem zunächst Aluminium und anschließend mit Hilfe eines Trägergases Kalk (CaO) in das Roheisen eingeblasen werden,
dbdurch geebneichnet ,
daß mit einer Menge von 2 - 20 N1 Trägergas/kg Entschwefelungsmittel zusammen mit dem Kalk ein in der Roheisenschmelze gasabspaltender Feststoff eingeblasen wird.1. A process for desulfurizing pig iron in a pan, in particular in a torpedo pan, in which first aluminum and then lime (CaO) are blown into the pig iron with the aid of a carrier gas,
db by the level,
that with a quantity of 2 - 20 N1 carrier gas / kg desulphurizing agent, together with the lime, a solid which splits off gas in the pig iron melt is blown in. 2. Verfahren nach Anspruch 1,
dadurch gekennzeichnet,
daß als gasabspaltender Feststoff ein Erdalkalikarbonat und/oder ein Erdalkalihydrat zugesetzt wird.2. The method according to claim 1,
characterized,
that an alkaline earth carbonate and / or an alkaline earth metal hydrate is added as the gas-releasing solid. 3. Verfahren nach Anspruch 2,
dadurch gekennzeichnet,
daß als Erdalkalikarbonat Kalkstein oder Dolomit bzw. als Erdalkalihydrat Hydratkalk eingeblasen wird.3. The method according to claim 2,
characterized,
that limestone or dolomite is blown in as alkaline earth carbonate or hydrate lime is blown in as alkaline earth hydrate. 4. Verfahren nach Anspruch 1 bis 3,
dadurch gekennzeichnet,
daß ein Gemisch, bestehend aus 40 - 70 Gew.-% Kalk und 30 - 60 Gew.-% gasabspaltendem Feststoff, in das Roheiser eingeblasen wird.4. The method according to claim 1 to 3,
characterized,
that a mixture consisting of 40-70% by weight of lime and 30-60% by weight of gas-releasing solid is blown into the pig iron. 5. Verfahren nach Anspruch 1 bis 4,
dadurch gekennzeichnet,
daß dem eingeblasenen Gemisch ein Anteil an Kohlenstoff oder kohlenstoffhaltigen Substanzen, wie Ruß, Anthrazit, Graphit, Petrolkoks, im Bereich von 1 - 10 Gew.-% zugesetzt wird.5. The method according to claim 1 to 4,
characterized,
that a proportion of carbon or carbon-containing substances, such as carbon black, anthracite, graphite, petroleum coke, is added to the blown-in mixture in the range of 1-10% by weight. 6. Verfahren nach Anspruch 1 bis 5,
dadurch gekennzeichnet,
daß dem eingeblasenen Gemisch 1 - 10 Gew.-% Flußspat zugesetzt wird.6. The method according to claim 1 to 5,
characterized,
that 1-10% by weight of fluorspar is added to the blown-in mixture. 7. Verfahren nach Anspruch 1 bis 6,
dadurch gekennzeichnet,
daß die Fördergasmenge 3 - 8 Nl Trägergas/kg Entschwefelungsmittel beträgt.7. The method according to claim 1 to 6,
characterized,
that the amount of feed gas is 3 - 8 Nl carrier gas / kg desulfurizing agent. 8. Verfahren nach Anspruch 1 bis 7,
dadurch gekennzeichnet,
daß das Gemisch mit komprimierter Luft in die Roheisenschmelze eingeblasen wird.8. The method according to claim 1 to 7,
characterized,
that the mixture is blown into the pig iron melt with compressed air.
EP84107487A 1984-06-28 1984-06-28 Method for desulfurizing pig iron Expired EP0166019B1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
DE8484107487T DE3474568D1 (en) 1984-06-28 1984-06-28 Method for desulfurizing pig iron
AT84107487T ATE37902T1 (en) 1984-06-28 1984-06-28 PIG IRON DESULPHURIZATION PROCESS.
EP84107487A EP0166019B1 (en) 1984-06-28 1984-06-28 Method for desulfurizing pig iron
US06/743,854 US4586955A (en) 1984-06-28 1985-06-12 Process for desulphurizing hot metal
CA000485473A CA1239022A (en) 1984-06-28 1985-06-27 Process for desulphurising hot metal
AU44244/85A AU570805B2 (en) 1984-06-28 1985-06-27 Desulphurisation of molten iron
CN85104955.9A CN1003308B (en) 1984-06-28 1985-06-28 Molten metal desulfurization process

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP84107487A EP0166019B1 (en) 1984-06-28 1984-06-28 Method for desulfurizing pig iron

Publications (2)

Publication Number Publication Date
EP0166019A1 true EP0166019A1 (en) 1986-01-02
EP0166019B1 EP0166019B1 (en) 1988-10-12

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US (1) US4586955A (en)
EP (1) EP0166019B1 (en)
CN (1) CN1003308B (en)
AT (1) ATE37902T1 (en)
AU (1) AU570805B2 (en)
CA (1) CA1239022A (en)
DE (1) DE3474568D1 (en)

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FR2780070A1 (en) * 1998-06-22 1999-12-24 Elf Antar France METHOD FOR FOAMING A DAIRY COVERING A MELT STEEL BATH

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RU2159290C1 (en) * 1999-07-07 2000-11-20 ОАО "Новолипецкий металлургический комбинат" Methods of steel treatment on ladle
RU2156309C1 (en) * 1999-07-07 2000-09-20 ОАО "Новолипецкий металлургический комбинат" Method of ladle treatment of steel
RU2203963C2 (en) * 2001-01-16 2003-05-10 Открытое акционерное общество "Северсталь" Steel processing method
RU2185448C1 (en) * 2001-06-28 2002-07-20 Открытое акционерное общество "Новолипецкий металлургический комбинат" Method of treatment of steel in ladle
RU2184154C1 (en) * 2001-06-28 2002-06-27 Урцев Владимир Николаевич Method for producing hot rolled sheet product
RU2204613C2 (en) * 2001-07-23 2003-05-20 Открытое акционерное общество "Северсталь" Out-of-furnace steel refining method
RU2186857C1 (en) * 2001-12-18 2002-08-10 ООО "Техномаг" Method for manufacture of round section rolled products
RU2201458C1 (en) * 2002-06-04 2003-03-27 ООО "Сорби стил" Method of modification of steel
RU2286393C1 (en) * 2005-04-04 2006-10-27 Техком Импорт Экспорт Гмбх Method for reducing of steel in ladle
US9365907B1 (en) 2013-03-14 2016-06-14 ALMAMET USA, Inc. Conversion of troublesome lime fines to useful high quality fluidized lime in feeding flux lime to a BOF converter
RU2562848C1 (en) * 2014-07-11 2015-09-10 Федеральное государственное бюджетное учреждение науки Институт металлургии Уральского отделения Российской академии наук (ИМЕТ УрО РАН) Method of steel deoxidation in ladle
KR20220075376A (en) * 2019-09-30 2022-06-08 자미폴 리미티드 Molten iron desulfurization in the Kanbara reactor (KR) process

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Also Published As

Publication number Publication date
ATE37902T1 (en) 1988-10-15
AU570805B2 (en) 1988-03-24
EP0166019B1 (en) 1988-10-12
AU4424485A (en) 1986-01-02
CN1003308B (en) 1989-02-15
CN85104955A (en) 1987-01-07
DE3474568D1 (en) 1988-11-17
CA1239022A (en) 1988-07-12
US4586955A (en) 1986-05-06

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